Twist arrestors for yarn twisters



April 16, 1957 H. cRouzET TWIST ARRESTORS FOR YARN TWISTERS Filed May 14, 1956 INVENTOR. /'/E/V,/ (190025 r ATTORNEY United States Patent TWIST ARRESTORS FOR YARN rwrsrnns Henri Crouzet, Roanne, France, assignor to Ateliers Roannais de Constructions Textiles, Roanne, France, a limited liability company of France Application May 14, 1956, Serial No. 584,503

Claims priority, application France June 6, 1955 6 Claims. (Cl. 57-106) This invention relates to a twist-arresting device for use with uptwisters or downtwisters and has for an object to provide a device of the above type having novel and improved characteristics.

When a twist is given to a filament bundle on an uptwister, that is a device where the feeding spool rotates, or on a downtwister, such as a ring twister or belt spindle where the winding spool rotates, the twist given to the filament bundle has a tendency to feed back along the bundle. In order to limit this feeding back of the twist it is common practice to cause the bundle to slide over one or more fixed edges or surfaces or to follow a sinuous path on a contact device, or to make a turn around one or more idler rollers in order to arrest the feed of the twist at the desired point.

In all these cases the twist arresting device introduces a supplemental tension which in the case of an uptwister increases the tension on the filaments and in the case of a downtwister decreases the filament tension.

It is accordingly a further object of this invention to provide a device for arresting the back feeding of the twist without creating an appreciable complementary tension, either positive or negative.

The present invention provides a twist arresting device consisting of a freely rotating member having a series of edges, for example a polygonal member. This member, due to its rotation, does not create any complementary tension in the filament bundle and the edges engage the bundle to stop the back feeding of the twist.

The number of faces and therefor the number of edges of the polygonal member may vary. For example, a triangular, square, hexagonal or octagonal member may be used.

It is of course possible to use for the twist arresting one or more idler rollers of the above shape, around which the bundle passes. This bundle may make a fraction of a turn or a complete turn or several turns on said idler rollers.

The accompanying drawing shows one form of the device as used on an uptwister and on a downtwister.

In the drawings:

Fig. 1 is a diagrammatic view showing the device applied to an uptwister;

Fig. 2 is a similar view showing the device applied to a ring twister;

Fig. 3 is a detail view showing on a large scale the behaviour of the bundle while passing around the twist arrestor; and

Fig. 4 is a view similar to Fig. 1 showing an uptwister provided with two twist arrestors for each spindle.

2,788,634 Patented Apr. 16, 1957 Referring to Fig. 1 a spool 2 is shown as mounted on a rotative spindle 3 of an uptwister having a rotating guide 4 through which the filament bundle 5 passes as it is unwound from the spool 2. Above the guide 4 the bundle 5 passes around the triangular portion 7 of an idler pulley '6 which is mounted to turn with the rotating guide 4.

The rotating edges A, B and C of the idler pulley 6 arrest the twist in the same way as a fixed edge but without creating a complementary tension in advance of the roller as the said edges are a part of a freely rotating member.

Fig. 2 shows a downtwister comprising a rotating spindle 9 having a ring 10 carrying a traveler 11 of the usual form. The filament bundle 13 passes around a roller 6 of the type previously described for arresting the twist, then through an axial guide 12 and through traveler 11 to the rotating spindle 9.

In this embodiment the bundle is twisted by the ring twister as it is wound onto the spindle 9. The twist however cannot pass the triangular idler roller 6 and is thus confined to the yarn below the idler.

It is of course possible to use two or several idler rollers in series as shown in Fig. 4. The idler pulley 6 in Fig. 4 is fixed on the rotating guide 4 as in Fig. 1 to stop the twist and prevent it from feeding back along the bundle. Idler pulley 6a rotates about a fixed axis.

The device of Fig. 4 confines the twist to a very small part of the bundle equivalent to the distance between the triangular idler rollers 6 and 6a. A very regular and a high twist can thus be produced.

Other embodiments will be apparent to a person skilled in the art.

What is claimed is:

1. A twist arrestor for yarn twisters having twisting means to impart a twist to a bundle of filaments, comprising an idler roller around which said bundle passes in advance of the twisting means, said roller being polygonal in cross section with a plurality of flat sides intersecting in angular edges, said edges being in contact with said bundle and being adapted to arrest the twist without introducing complementary tension to said bundle.

2. A twist arrestor as set forth in claim 1 in which said roller is triangular in cross section.

3. A twist arrestor as set forth in claim 1 in which said twisting means comprises an uptwister having a rotating yarn guide, and said idler roller is mounted to turn with said guide.

4. A twist arrestor ts set forth in claim 3 having a second twist arrestor comprising an idler roller of polygonal cross section mounted to rotate about a fixed axis and spaced from said first roller to provide a twisting zone therebetween.

5. A twist arrestor as set forth in claim 1 in which said twisting means comprises a downtwister and said roller is mounted in advance of said twister to rotate about a fixed axis whereby the twist is confined to a zone between said roller and said downtwister.

6. A twist arrestor as set forth in claim 5 in which said twister is a ring twister.

No references cited. 

